Review of conformal displays: more than a highway in the sky

Abstract

A head-worn display combined with accurate head-tracking allows one to show synthetically generated symbols in a way that they appear as a part of the real world. Depending on the specific research context, different terms have been used for the ability to show display elements as parts of the outside world. These include contact analog, scene linked, augmented reality, and outside conformal. While the famous highway in the sky was one of the first applications in avionics, over the years more and more conformal counterparts have been devised for aircraft-related instruments. Among them are routing information, navigation aids, specialized landing displays, obstacle warnings, drift indicators, and many more. Conformal displays have been developed for more than 40 years. We present a review of some results, as well as look ahead to research trends for the next years. We suggest that naturalism is not the best choice for the design of conformal displays. Instead, more abstract representations often yield better pilot acceptance.